1. Field of the Invention
This invention relates to pilots for waste gas flare stacks and more particularly to pilots having a pilot burner head at the top of a flare stack.
2. Brief Description of the Prior Art
It has heretofore been proposed in order to ignite the combustible waste gas delivered to the top of a flare stack to provide a plurality of gas burning pilots around the periphery of the flare stack at the discharge end, the number of pilots being determined by the diameter of the flare stack.
The peripherally located pilots heretofore available included upwardly directed burner heads and burner heads directed inwardly toward the discharging stream of combustible gas.
In forced draft systems, the fan, customarily having two operating speeds, was usually located at or near the bottom of the stack, and was either manually or automatically controlled. This gave rise to a situation where there could be a very low gas flow with a very high air blower flow. This condition gave rise to problems of ignition of the waste gas by the pilot. Another situation also occurred when there was very low gas flow and no blower flow where the gas, being heavier than air, gave rise to the possibility of down flow of the gas, and admixture of the gas with air near the ground thereby creating an explosion hazard.
The use of a plurality of peripherally disposed continuously operating gas pilots as referred to above also resulted in substantial waste of pilot gas.